Eye motion program: It is proposed to develop techniques and to explore the basic mechanisms of horizontal eye motion in human subjects, considering (a) the parameters of position, velocity and acceleration, (b) the time relationship of eye motion with respect to stimulus motion, and (c) the relative time relationships of motion of one eye with respect to the other eye. Photoelectric pickup devices are used for monitoring eye position, with the stimulus pattern and electronics designed to give the appropriate velocity and acceleration information. Cross-correlation techniques are used in (b) and (c) above, using a commercially available correlator. Extensive statistical evaluation of the data is required, in order to try to separate abnormal results from normal results on a statistically valid basis. ERG and VER measurements: A new method of evoked potential measurement (Synchronous Detection) has been in use for some time. Considerable effort has been devoted to this method in order to define its advantages and disadvantages compared with more conventional methods of signal averaging. Both of these methods of data processing represent particular applications of cross-correlation techniques, and the general topic of cross-correlation methods has been studied to try to determine the most appropriate means of testing. This has led to the concept of a more general type procedure involving some of the characteristics of both of the methods mentioned above, and it is proposed to carry out studies involving these three different methods of examination, and to attempt to define the ranges and best means of application of each of them.